Microfluidic technology has been applied to expanding fields of research and analysis in an effort to increase speed, efficiency and accuracy of that research. Typically, microfluidic systems have at their core a microfluidic device, element or cassette which functions as a liquid integrated circuit for moving materials around, mixing, separating and measuring properties of those materials.
A number of different technologies have been applied to the fabrication of these microfluidic devices. For example, initial microfluidic devices were generally fabricated from silicon wafers using photolithographic techniques commonly exploited in the electronics industries. See, e.g., U.S. Pat. No. 4,908,112 to Pace, and Terry et al., IEEE Trans. Electron. Devices (1979) ED-26: 1880). In brief, grooves and or depressions are etched into the surface of a first silicon substrate while a second substrate is overlaid on the first, sealing the grooves and depressions to define channels and chambers, respectively, within the device. Glass substrates have also been fabricated in a similar fashion. See, U.S. Pat. No. 5,882,465.
Polymer fabrication methods have also been used in the production of these devices. Specifically, polymeric substrates are provided having grooves fabricated into their surface using, e.g., injection molding techniques, embossing techniques or laser ablation techniques. See U.S. Pat. Nos. 5,885,470 and 5,571,410.
U.S. Pat. No. 5,376,252 to Ekstrom on the other hand describes the use of a flexible gasket or spacer placed between two planar substrates, where channels are defined within the gasket or spacer.
While many of the above-described methods have produced functional microfluidic devices, their exist areas for improving the fabrication process for microfluidic devices, e.g., excessive costs, sensitivity to material defects, and artifacts of fabrication that materially affect the functioning of the device, e.g., channel collapse in polymer substrates, etc.